Prompted by two clinical trials which have suggested distinct but apparently opposite effects of lipid emulsions on the production of and lymphocyte responses to IL-2 we have examined the effects of pharmacological concentrations of three lipid emulsions currently in clinical use on IL-2 related interactions in vitro.

IL-2 radioiodinated by this method binds with high affinity to receptors present on phytohemagglutinin-stimulated peripheral blood lymphocytes and should be useful for the study of receptor structure and function.

Since IL2 plays a role in lymphocyte proliferation and differentiation, the ability of suramin to inhibit binding of IL2 to its receptor may explain, in part, the in vivo immunosuppressive activities of suramin.

Particular emphasis has been dedicated to Lymphokine Activated Killers in association with Interleukin2 (IL2) and Tumor Infiltrating Lymphocytes, which have shown a very strong and specific anticancer activity.

Using protein extracts from El4 lymphoma cells we show that the binding of lymphocyte-specific factors interacting with the two so-called purine boxes (Pu-boxes) of the interleukin 2 (IL-2) enhancer are missing in CsA-treated cells.

It is conceivable that administration of intralipid to preterm infants may interfere with the binding of IL-2 to the specific receptors on their activated lymphocytes, with a possible subsequent suppression of their immune response.

The role of membrane fluidity in the process of signal transduction after binding of Interleukin-2 (Il-2) to its specific cell-surface receptor was investigated in lymphocytes from normal donors and patients with Chronic Lymphocytic Leukemia (CLL).

Although the H (beta) chain expressed on lymphocytes can bindIL-2 with a Kd value of 1 nM (intermediate affinity), transfected fibroblasts expressing the H chain cannot bind IL-2, suggesting the involvement of other lymphocyte-specific factors for the function of the H chain.

Our approach using fresh human tumors as both targets in cytotoxicity assays and stimulators in proliferative assays with other appropriate controls makes possible a careful analysis of the reactivities present following either direct expansion in Interleukin 2 (IL-2) or following mixed lymphocyte tumor interaction and subsequent limiting dilution cloning.

The failure of the antibodies to neutralize the biological activity of recombinant interleukin-2 (IL-2) in lymphocyte proliferation assays and to bind to the native lymphokine suggests that they may not affect IL-2-dependent cellular immune functions in vivo.

Since lymphocytes devoid of the I chain were not available, we employed functional depletion of the I chain from a mouse T cell line CTLL-2 transfected with cDNA for the human H chain and its defective mutants which can bindIL-2 but cannot transduce a growth signal.

The biologic activity of this analog is greatly reduced, primarily as a result of decreased affinity to the beta/gamma IL-2 receptor complex; however, it is only weakly antagonistic to the IL-2 response of normal peripheral blood lymphocytes.

These clinical studies have demonstrated the efficacy of using scintigraphy to detect activated lymphocytes, which correlate with the severity of tissue lymphocytic infiltration and that scintigraphy with radiolabeled IL2 can be used for monitoring the efficacy of specific therapies.

Although in patients with good prognosis the ability of PBL to respond to IL-2 was not changed before and after treatment, in patients with poor prognosis the response was significantly increased after chemotherapy.

The protocol is based on surgical debulking followed by implantation into the tumor bed of autologous lymphocytes that have been stimulated with phytohemagglutinin-P and then cultured in vitro in the presence of interleukin 2.

Soluble IL-2R protein thus prepared retained the ability to bindIL-2 specifically and suppressed the in vitro IL-2-mediated immune responses, including proliferation of IL-2-dependent cell line (CTLL-2), induction of secondary cytotoxic T lymphocytes (CTL) and the mixed lymphocyte reaction (MLR), but did not suppress the growth of IL-3-dependent cell line.

Two monoclonal antibodies (designated as KNT-1 and KNT-2) out of six established clones reacted with natural human IL-2 molecule obtained from cultured human peripheral blood lymphocytes (PBL) stimulated with PHA-P and TPA.

The following aspects were examined: the morphological pattern of IL-2 stimulated lymphocytes; the ability of these cells to recognize, bind, attack and destroy tumoral lines; their cytochemical and immunological (CD) feature.

These data suggest the interaction of IL-2 and the high-affinity IL-2 receptor on human PBMC or peripheral blood lymphocyte is required for maximal secretion of IL-1 beta, TNF-alpha, TNF-beta, and IFN-gamma.

Lymphocyte proliferation was inhibited by anti-IL2 receptor and anti-IL2 antibodies as well, indicating that zinc augments signal transduction through IL2 receptors through enhancement of the interaction between the IL2 and IL2 receptors.

Twenty-five patients with disseminated cancer (nine with renal cell carcinoma, five with melanoma, three with Hodgkin's lymphoma and chronic myelocytic leukemia [CML], two with soft tissue sarcoma, one each with large-cell lymphoma, breast cancer, and colon cancer), 13 males and 12 females, aged 25 to 68, were treated with recombinant human interleukin-2 (rIL2) by continuous infusion and adoptive transfer of autologous lymphocytes activated in vitro with IL2.

These FcR+ cells are also capable of antibody-dependent cytotoxicity (ADCC), which can be detected using fresh human peripheral blood lymphocytes (PBL) directed to murine targets, however, PBL-mediated ADCC to human tumors usually is very low, requiring a stimulation of the PBL, which also can be accomplished with IL-2.

Dose-response curves using increasing concentrations of IL-2 and IL-3 and isobologram analysis of these interactions revealed a clear synergy of action between the two growth factors in inducing proliferation of unfractionated PBL, purified T cells, mitogen-activated lymphocytes, and alloantigen-stimulated T cells.

In contrast, TIL from the other three of eight melanoma and all three sarcoma contained one-third Tac-positive cells as assessed by flow cytometry analysis, and expressed surface non-Tac (p70-75) and Tac (p55) peptides by [125I]IL-2cross-linking.

Ultrastructural and biochemical experiments showed that clathrin-independent endocytosis of IL2 receptors exists constitutively in lymphocytes and is coupled to their association with detergent-resistant membrane domains.

The high buoyant density lymphocytes, depleted of NK cells, had no targetable activity, but were able to generate over several days, targetable T cell activity in the presence of a TCR cross-linking signal plus IL-2.